Review Article

Fecal Microbiota Transplantation: A New Therapeutic Attempt from the Gut to the Brain

Table 1

Characteristics, consequences, and application level of FMT in neuropsychological diseases.

Disease typesAlterations of gut microbiotaAltered substances caused by microbial dysbiosisApplication level of FMTReferences

Neurological diseases
 Parkinson’s diseaseIncrease in Verrucomicrobiaceae, Ruminococcaceae, Proteobacteria, Clostridiaceae, Enterobacteriaceae, Bifidobacteriaceae, Lactobacillaceae, Pasteurellaceae, Christensenellaceae, Lactobacilli, Akkermansia, Ralstonia
Decrease in Firmicutes, Prevotellaceae, Coprococcus, Bacteroides fragilis, Blauti, Roseburia, Faecalibacterium
α-Synuclein, LPS, SCFAs, hydrogen productionPatient & animal[4, 13, 14]
 Alzheimer’s diseaseIncrease in Escherichia, Shigella, Chlamydia pneumoniae, Borrelia burgdorferi, Treponema pallidum, Burkholderiaceae, Staphylococcaceae, Porphyromonas gingivalis, Propionibacterium acnes
Decrease in Eubacterium rectale, Bacteroides fragilis
Inflammatory cytokines (IL-6, CXCL2, NLRP3, IL-1β, IL-10), Aβ, GABA, BDNF, DHAPatient & animal[5, 6, 13, 15]
 Multiple sclerosisIncrease in Firmicutes, Clostridium, Escherichia Shigella
Decrease in Bacteroides, Faecalibacterium, Eubacterium rectale, Corynebacterium, Fusobacteria
Proinflammatory cytokines, butyrate, lipid 654Patient & animal[13]
 EpilepsyIncrease in Firmicutes, Proteobacteria, Clostridium, Cronobacter, Akkermansia, Ruminococcus, Coprobacillus, Clostridium XVIII, Atopobium, Holdemania, Dorea, Saccharibacteria, Delftia, Paraprevotella, Gemmiger, Neisseria, Coprococcus, Fusobacterium, Methanobrevibacter, Phascolarctobacterium, Roseburia
Decrease in Bacteroidetes, Actinobacteria, Prevotella, Bifidobacterium
Proinflammatory cytokines (TNFα, IL-6, IL-1β), dopamine receptors D1 and D2Patient & animal[16, 17]
 Tourette SyndromeIncrease in Bacteroidetes; in particular, Bacteroides, Odoribacter, and Oscillospira were identified as potential microbial biomarkersSCFAs, D-alanine, tyrosine, dopaminePatient & animal[18]
 Myalgic encephalomyelitis/chronic fatigue syndromeIncrease in Roseburia, Holdemania, Enterococcus, Streptococcus spp.
Decrease in most Bacteroidetes genera.
Lactic acid, LPS, LPS-binding protein, soluble CD14, oxidative stressPatient & animal[1921]
 Guillain-Barré SyndromeCampylobacter jejuni infection is associated with GBS while Enterococcus faecalis as a potential protective roleLPS, peripheral nerve gangliosidesAnimal[22, 23]
 StrokeDecreased neuronal injury and improved cognitive performance were observed in diabetic mice with bilateral common carotid arteries occlusion after receiving Clostridium butyricumTrimethylamine N-oxideAnimal[24, 25]
 Amyotrophic lateral sclerosisIncrease in Dorea
Decrease in Butyrivibrio fibrisolvens, Firmicutes, Peptostreptococcus, Escherichia coli, Oscillibacter, Anaerostipes, Lachnospira
ButyrateAnimal[2628]
 Huntington’s diseaseIncrease in Bacteroidetes
Decrease in Firmicutes, Lachnospiraceae, Akkermansiaceae
Methionine, glycineAnimal[29, 30]
Psychiatric diseases
 Autism spectrum disorderIncrease in Bacteroides, Barnesiella, Clostridium, Roseburia
Decrease in Bifidobacterium, Coprococcus, Dialister, Faecalibacterium, Prevotella, Streptococcus
Butyrate, lactatePatient & animal[3133]
 Bipolar disorderIncrease in Bacteroidetes, Actinobacteria, Coriobacteria, Lachnospira, Enterobacteriaceae, Flavonifractor
Decrease in Firmicutes, Ruminococcaceae, Roseburia, Faecalibacterium, Coprococcus
ButyratePatient & animal[3437]
 DepressionIncrease in Enterobacteriaceae, Prevotella, Klebsiella, Alistipes
Decrease in Lachnospiraceae, Faecalibacterium, Coprococcus, Dialister, Ruminococcus, Lactobacillus, Bifidobacterium
Butyrate, inflammatory cytokinesPatient & animal[36, 38, 39]
 AnxietyIncrease in Fusobacterium, Ruminococcus, Escherichia Shigella
Decrease in Faecalibacterium, Eubacterium, Sutterella
Animal[40, 41]
Other system-related neurological diseases
 Hepatic encephalopathyIncreases in Enterobacteriaceae, Streptococcaceae, Porphyromonadaceae, Staphylococcaceae, Enterococcaceae
Decrease in Lachnospiraceae, Ruminococcaceae, Rikenellaceae, Clostridium XIV, Phascolarctobacterium
Ammonia, urease, SCFAs, aromatic amino acidsPatient & Animal[42, 43]
 Neuropathic painAssociated: Lactobacillus fermentum KBL374 & KBL375, Bacteroides fragilis, Escherichia coli, Lactobacillus, Streptococcus spp., Enterococcus spp., Corynebacterium glutamicum, Peptostreptococcus, Clostridium sporogenesLPS, bacterial flagellin, indole, SCFAs, PUFAs, BAsPatient & animal[44]
 Sepsis-associated encephalopathyAssociated: absence of anaerobes, including Staphylococcus species and Escherichia coli, with CDI, high relative abundance of pathogenic gram negatives, and EnterococciLPS, SCFAs, BAsPatient & animal[45]

LPS: lipopolysaccharide; SCFAs: short-chain fatty acids; IL-6: interleukin-6; CXCL2: C-X-C motif chemokine ligand 2; NLRP3: recombinant NLR family, pyrin domain containing protein 3; IL-1β: interleukin-1β; IL-10: interleukin-10; Aβ: amyloid β-protein; GABA: γ-aminobutyric acid; BDNF: brain-derived neurotrophic factor; DHA: docosahexaenoic acid; TNFα: tumor necrosis factor-α; PUFAs: polyunsaturated fatty acid; Bas: bile acids.